Weight for load balancing cranks



A ril 7, 1936. l N MARSH 2,036,592

WEIGHT FOR LOAD BALANCING CRANKS Filed March 5, 1934 F'IG.2 HALLAI NMARSH /N 5 N TOR IRNE) Patented Apr. 7, 1936 UNITED STATES PATENT OFFICE 1 Claim.

The object of my invention is to provide an improved form of weight for the type of load balancing cranks described in Patent No. 1,866,049, issued to me July 5, 1932.

A specific object of my invention is to provide a weight which may be applied to a crank of this description in two positions, in one of which it has a greater counterbalancing effect and in the other a less effect and also a reduced radius from the center of rotation of the crank.

In the attached drawing, Fig. 1 illustrates in elevation a crank provided with a plurality of weights, and Fig. 2 illustrates the manner in which the bo1t-holes through the weights are spaced.

Referring to Fig. 1, H] is a crank shaft shown in end elevation, II a key for attaching the crank to the shaft, l2 a crank provided with the conventional crankpin holes l3, I4 is a radial extension of the crank and I5l5 are lateral extensions of the crank forming a square shoulder l6, I'l--I'l are weights and l8--I 8 are throughbolts for holding the weights in position on the crank.

Referring to Fig. 2, the slab weights I'l-l'l are shown in two positions, one being the reverse of the other. The distance A between the bolt holes is the same in all weights of one size (regardless of thickness) but the spacing B is materially less than the spacing C. In Fig. 1 the slabs are placed in the position Ila until the corner IQ of the stack closely approaches the are 20 which represents the maximum radius of rotation permitted by foundations of other fixed objects. A considerable number of the same slabs may then be placed in the reversed position l'lb before the second corner 2| again approaches the are 20.

The improved form of weight here disclosed permits the use of a single type of weight to cover a very wide range of counterbalancing load. Modern deep wells require very large and highly variable counterbalance effects, and it is highly 5 advantageous to be able to standardize on one form of weight.

The lateral extensions on the crank with square shoulders for the abutment of the weights indicate a preferred form of crank particularly adapt- 10 ed to very heavy weighting, greatly relieving the strain on the throughbolts. The improved form of weight may, however, be used with the ordinary form of straight faced crank shown in the patent above referred to and indicated in Fig. 1 of the present drawing by the broken lines 2222.

I claim as my invention:

In a crank counterbalance assembly and in combination with a crank: bolts projected from a face of said crank perpendicular to its plane of rotation; a first stack of weights held by said bolts against said face; a second stack of weights held by said bolts against the face of said first stack which is parallel to said crank face, the outermost portion of said second stack as regards 25 the center of rotation of said crank lying substantially within the largest circle described by the revolution of said first stack, the individual weights comprising both said stacks being substantially identical rectangular slabs provided with bolt holes so arranged that their mean distance from one end of each said slab is materially less than their mean distance from the other end of each said slab.

HALLAN N. MARSH. 

